There are various ideas on how a tree should be watered, but the main theme that most experts agree on is that a tree should be watered deeply rather than frequently. Water should be kept away from the base of the tree and water should not spray onto the fruit or leaves of the tree. Water that is sprayed onto the leaves and fruit can increase the chance of various types of mildew, fungal and bacterial problems. If the soil becomes too wet at the base of the tree it can cause soil-born fungal diseases such a crown rot.
Currently, there are many ways to water various plants, shrubs, fruit trees and trees. Rotary sprinklers, which are mainly used for watering lawns and gardens, are designed to operate at medium to high water volumes. If the water volume is turned down too low, most of the rotary designed sprinklers will not operate properly and will have a tendency to stall in one position and not rotate back and forth. This can be a problem when watering newly planted trees which need water in a small contained area at low volumes.
Oscillating sprinklers are generally designed to be used for lawns and gardens, and most do not operate at low water volumes. Oscillating sprinklers typically shoot volumes of water in both an upward and outward pattern in order to cover large areas. Often this method of watering sprays water on the fruit and leaves of trees and shrubs increasing the risk of fungal diseases.
Dropping a garden hose near the base of a tree and turning the faucet to a very low water volume is especially common when watering newly planted and young trees. However, often the water is concentrated on one side of the tree while the opposite side may lack the ideal amount of water. Irrigating a 360 degree zone around the tree is preferable as it encourages root growth in all directions.
Another popular method of watering is the soaker hose. This method entails wrapping the hose in a spiral pattern around the base of the tree. This may not be a concern for a single tree, however, when one has many trees to water it can be a time consuming event to unwrap the soaker hose from one tree and wrap it around the next. Another disadvantage is, as the tree grows, more and more soaker hose is required to effectively reach the areas that need to be watered. With newly planted trees, shrubs or plants it can be difficult to purchase a standard length soaker hose that is short enough to accommodate the limited area that needs to be watered. If the soaker hose is too long, too many wraps around in a tight area can apply water too quickly and cause water waste due to run off or the wraps can extend too far outside the root ball system which will not benefit the tree and result in water waste. When mowing the lawn, it is prudent to unwrap the soaker hose from around the tree so the hose does not get caught in the mower blades. This is both laborious and time consuming as the hose will have to be wrapped back around the tree after mowing. Grass around the tree can also be damaged if the soaker hose is left for a long period of time leaving an unsightly spiral imprint in the grass when the hose is removed.
A common solution to watering selected plants or areas are the low volume drip/sprinkler systems. For example, RainBird® makes an array of low volume drip/sprinkler systems that are attachable to a garden hose. The RainBird® systems and other low volume drip/sprinkler systems have a variety of low water volume emission devices or spray heads available such as full/half/quarter circle, strip patterns, and the like. Typically these units are on a long length of thin, plastic tubing lying within landscaping with the desired spray heads inserted into the tubing near plants or shrubs. Once in position, they are not easily moved and are crushed or severed if ran over by a mower.
In the case of a tree, a low volume system such a RainBird® drip/sprinkler system may be useful during the youth of the tree as these systems produce a very low volume spray and are somewhat adjustable to avoid spraying the tree. However, as the tree matures and a larger watering pattern is needed, these low volume systems cannot spray a pattern large enough to efficiently water a mature tree. The low volume sprinkler system has to be removed and replaced with a sprinkler system capable of producing a larger spray pattern at higher water volumes to support a mature tree. This becomes very costly as well as time consuming.
U.S. Pat. No. 4,010,898 issued to Williams, discloses a semi-permanent, semi-looped conduit that has multiple spray nozzles along the conduit for distributing liquid outward from the plant/tree in a fan-like overlapping pattern. One issue with this configuration is that the spray nozzles do not spray a narrow pattern or oscillate back and forth allowing the water time to soak into the ground before the next pass. Additionally, there is no option of interchangeable spray heads to accommodate different soil types and watering requirements of the plant or there. Williams has no method of controlling or adjusting the watering zones around the tree and there is no easy method of shutting off any of the spray nozzles to accommodate areas that may not require irrigation. Even though Williams' system eliminates the wrapping issues of the soaker hose method, it has no variability with respect to plant/tree trunk size; therefore it is optimal for only one size or variety of tree.
U.S. Pat. No. 4,778,111 issued to Leap, makes another attempt to improve the soaker hose idea with two tubular arms (short lengths of soaker hose) that wrap around a tree. Although this can reach around a large tree as well as around a smaller tree, with a small tree there will be considerable overlap of the two tubular arms creating one extremely wet side as there will be double watering on one side. Leap discloses no means of watering zone control such as the ability to shut off one or more of the spray nozzles for areas that may not require irrigation or overlap. There is no option for modifying the spray nozzle function to accommodate different soil types and watering requirements of the plant or tree. The spray pattern also shows that it will likely spray onto the trunk area which can cause some types of soil born fungal diseases to attack the base area of the tree. As in U.S. Pat. No. 4,010,898 issued to Williams, it does not have a single spray pattern that oscillates back and forth giving the ground time to soak in the water before the next pass of water is applied.
U.S. Pat. No. 5,285,968 issued to McSheehy, discloses a one-piece molded water chamber in the form of an annulus having a large open segment which permits the water chamber to surround the trunk of a tree for watering. Although McSheehy surrounds the trunk of a tree, it fails to provide any ability to efficiently adjust to watering varying tree sizes. As with Williams and Leap above, McSheehy has little or no adjustability with regard to spray head design and watering zone control.
Many people rely on their in-ground lawn sprinkler systems to not only water their grass but also their trees. Lawns require shallow watering, around six inches, and frequent irrigation. This is not always the best irrigation for trees. Trees and grass compete for the water that is applied. Since most in-ground systems are set up to only apply enough water to keep grass healthy, both the grass and tree are not supplied with enough irrigation. Increasing in-ground irrigation in the zones that have trees, increases water costs and water waste. Additionally, most in-ground systems are broken into watering zones. Each zone can contain many sprinkler heads and each zone is controlled by the same timer and on/off valve. This makes it difficult to apply water only in the areas that benefit the tree without over-watering the other areas within the zone. Unlike grass, trees should be watered less frequently and at a depth of at least eighteen inches.
There is a need for a sprinkler system that can easily be placed around variable sized trees, applies water at an even, adjustable rate 360 degrees around the tree, and is able to irrigate to a depth that is healthy for any variety or size of tree. Additionally, the desired sprinkler system needs to accommodate low volume as well as high volume watering needs while avoiding excessive watering and runoff. This sprinkler system needs to accomplish all of this while conserving water and being beneficial for both the tree and the surrounding grass.